TWI425565B - Etching apparatus and etching method - Google Patents

Description

Etching method and etching device

The present invention relates to an etching method and an etching apparatus for etching a layer to be processed such as an insulating film formed on a surface of a workpiece such as a semiconductor wafer.

In general, when forming an integrated circuit of a semiconductor article, various processes such as a film formation process, a conversion process, an oxidative diffusion process, and an etching process are repeated on the surface of a semiconductor wafer such as a germanium substrate. Thereby, the desired integrated circuit is fabricated.

In the above various processes, for example, an etching process will be described as an example. In the etching process, generally, the surface of the layer to be processed of the object to be etched is used, and a photoresist or the like is used to form a patterned etching mask. By using the etching mask as a mask, the etching gas can be selectively used to selectively remove only the portion to be removed. Thereby, etching is performed only at the desired portion. Here, since the photoresist is generally composed of an organic material, heat resistance is not high. Therefore, when etching is performed to apply a pattern of a mask to a proper shape, the heat resistance of the mask should be considered, and etching should be performed at a relatively low temperature of about 200 °C. In general, plasma etching is used as the etching treatment at such a low temperature (for example, refer to Japanese Laid-Open Patent Publication No. Hei 5-21396).

An example of a conventional etching method using plasma will be described with reference to FIGS. 4A to 4E. 4A to 4E are process diagrams showing an example of a conventional etching method using plasma.

As shown in FIG. 4A, the surface to be processed 202 to be etched is formed into a predetermined pattern on the surface of the object W to be formed of a semiconductor wafer such as a germanium substrate. The processed layer 202 is, for example, an insulating film made of SiO ₂ or the like. Further, only a part of the upper side of the object to be processed is shown in the drawing.

Next, for the purpose of eliminating the adverse effect of the reflected light upon exposure of the photoresist described later, an anti-reflection film 204 made of, for example, an organic material is uniformly formed on the upper surface of the layer 202 to be processed.

Next, in the surface of the anti-reflection film 204 of the object to be processed W formed in this manner, the photoresist layer 206 is first uniformly formed with a predetermined thickness (see FIG. 4A). This photoresist layer 206 is selectively exposed to light, and then a part thereof is selectively removed to form an etching recess 208 (refer to FIG. 4B). That is, an etch mask 210 composed of a photoresist is fabricated. The etching recess 208 is formed in a groove shape or a hole shape depending on the pattern of the processed layer 202 to be removed.

Next, the anti-reflection film 204 exposed at the bottom of the etching recess 208 is removed by plasma etching (see FIG. 4C). Thereby, the surface of the processed layer 202 is exposed. Further, while the etching mask 210 is used as a mask, plasma etching is applied to etch the processed layer 202 composed of the SiO ₂ film (see FIG. 4D).

Thereafter, an ashing treatment using plasma is applied to remove the etching mask 210 and the reflection preventing film 204 composed of organic substances, respectively (see FIG. 4E). Thereby, the etching process is ended.

When the line width or the groove width or the aperture is relatively large, the shape of the layer to be processed 202 does not collapse, and the desired etching treatment can be performed. However, when the size of the line width or the like is required to be further increased, and the size of the line width or the like is, for example, 150 nm or less, in order to improve the resolution, it is necessary to use light penetration even for shorter wavelengths. The photoresist layer 206 is also formed by a high special photoresist.

However, such special photoresists are less resistant to plasma. Therefore, for example, as shown in FIG. 4C and FIG. 4D, when the plasma is processed, the opening portion 210A of the etching mask 210 composed of the photoresist is struck by the plasma, and is gradually enlarged and deformed. Accordingly, as shown in FIGS. 4D and 4E, the opening portion 212A of the processing groove 212 of the processed layer 202 is also wider than the predetermined size. That is, there is a possibility that the etching cannot be performed into an appropriate shape, and the desired etching pattern cannot be obtained.

In this case, the amount of removal by the plasma etching mask 210 (photoresist layer 206) can be considered, and it is considered to be a measure thicker than the thickness of the etching mask 210. However, when the etching mask 210 (the photoresist layer 206) is made too thick, when the photoresist layer 206 is exposed by exposure, the lower portion of the photoresist layer 206 is not sufficiently photosensitive, or the thickness of the photoresist layer 206 is The focus cannot be aligned. Therefore, the maximum thickness of the etching mask 210 is at most about 400 nm, and it is impossible to be larger than this thickness.

The present invention has been made in view of the above problems and is an effective solution to the invention. The object of the present invention is to prevent the deformation of the etching mask by thinly coating the surface of the mask with a plasma resistant film, and to provide an etching method and an etching apparatus which can more reliably produce a desired etching pattern without shape collapse. .

The present invention is an etching method for etching a layer to be processed formed on a surface of a substrate to be processed, comprising: a photoresist forming step of uniformly forming a photoresist layer on a surface of the object to be processed; and a mask forming step And forming a patterned etching mask by forming a predetermined etching recess in the photoresist layer; forming a plasma resistant film forming step, comprising: a bottom portion and a side surface of the etching recess, and the etching mask a plasma resistant film formed on the entire surface; a bottom plasma resistant film removing step of removing the plasma resistant film formed on the bottom of the etching recess; and a formal etching step in the bottom plasma resistant film removing step Thereafter, the etching mask is used as a mask to etch the processed layer.

According to the present invention, a plasma resistant film is formed on the entire surface of the etching mask, and since the general etching treatment for removing the processed layer is performed after removing the plasma resistant film located at the bottom of the etching recess of the etching mask, etching can be prevented. The reticle is deformed and the desired etch pattern without shape collapse can be more reliably produced.

For example, the thickness of the plasma resistant film formed on the bottom of the etching recess is thinner than the thickness of the plasma resistant film formed on the etching mask.

Further, for example, the plasma resistant film is formed by plasma CVD treatment at a temperature lower than the heat resistant temperature of the etching mask.

Further, it is preferable that an anti-reflection film is formed in advance on the surface of the layer to be processed. At this time, for example, before or after the plasma-resistant film forming step, a bottom reflection preventing film removing step of removing the anti-reflection film located at the bottom of the etching recess is performed.

Further, for example, after the main etching step, the plasma resistant film removing step of removing the plasma resistant film and the mask removing step of removing the mask are sequentially performed.

Further, for example, part or all of the plasma resistant film forming step, the bottom plasma resistant film removing step, and the above-described main etching step are performed in the same plasma processing apparatus.

Further, the present invention provides an etching apparatus for applying a predetermined etching treatment to a target object, comprising: a processing container capable of being evacuated; and a loading table provided in the processing container for loading the object to be processed a gas introduction means for introducing a predetermined gas into the processing container; a plasma forming means for plasmaizing the predetermined gas in the processing container; and means for controlling the gas introducing means and the plasma forming means The control unit performs a step of forming a plasma-resistant film on the entire surface of the etching mask formed on the surface of the layer to be processed of the object to be processed, and performing a step of forming a plasma-resistant film and a bottom electrode. a slurry-resistant film removing step of removing a plasma-resistant film formed on a bottom portion of an etching recess formed on the etching mask, or a part or all of steps in a formal etching step, which removes a bottom portion of the etching recess Further, the above-described processed layer is etched by using the etching mask covered with the plasma resistant film as a mask.

Furthermore, the present invention is a memory medium for storing a computer program for causing a computer to implement a control method for controlling a processing container capable of being evacuated; and being disposed in the processing container for loading a loading platform for processing a body; a gas introduction means for introducing a predetermined gas into the processing container; and an etching device for plasmaizing the predetermined gas in the processing container, and controlling the gas introduction And a means for forming the plasma, wherein the plasma resistant film forming step is formed by forming a plasma on the entire surface of the etching mask formed on the surface of the processed layer of the object to be processed. a resistance film and a bottom plasma resistant film removing step of removing a plasma resistant film formed on the bottom of the etching recess formed on the etching mask, and a part or all of the steps in the formal etching step, In addition to the bottom of the etching recess, the etching mask covered with the plasma resistant film is used as a mask to etch the processed layer.

Hereinafter, embodiments of the etching apparatus and the etching method of the present invention will be described in detail based on the drawings.

Fig. 1 is a schematic cross-sectional view showing an etching apparatus according to an embodiment of the present invention. 2A to 2H are process diagrams showing an etching method according to the first embodiment of the present invention. 3A to 3H are process diagrams showing an etching method according to a second embodiment of the present invention. Here, the plasma etching treatment is performed using a plasma generated by microwaves.

As shown in Fig. 1, the etching apparatus (plasma etching apparatus) 22 of the present invention has a processing container 24 integrally formed into a cylindrical shape. The side wall or bottom of the processing vessel 24 is constructed of a conductor such as aluminum and grounded. The inside of the processing container 24 is constituted by a sealed processing space S, and plasma is formed in this processing space S.

Inside the processing container 24, a loading table 26 on which, for example, a semiconductor wafer is loaded as a processed object is housed. The loading table 26 is formed in a flat disk shape, and is made of, for example, aluminum or ceramic treated with an alumite treatment. The loading table 26 is supported by a post 28 formed of, for example, aluminum or the like that is erected from the bottom of the processing container 24.

On the side wall of the processing container 24, an opening and closing gate valve 30 for moving the wafer into and out of the processing container 24 is provided. Further, an exhaust port 32 is provided at the bottom of the processing container 24. An exhaust passage 38 that sequentially connects the pressure control valve 34 and the vacuum pump 36 to the exhaust port 32 is connected. Thereby, the inside of the processing container 24 can be evacuated to a predetermined pressure as needed.

Further, the top of the processing container 24 is provided with an opening (having an opening). Here, the top plate 40 penetrating the microwave is provided in an airtight manner through the sealing member 42 such as an O-ring. The top plate 40 is made of, for example, a ceramic material such as Al ₂ O ₃ or the like. The thickness of the top plate 40 is set to be, for example, about 20 mm.

Next, a plasma forming means 44 for generating plasma by microwave is provided on the top surface of the top plate 40. Specifically, the plasma forming means 44 has a disk-shaped planar antenna member 46 provided on the top surface of the top plate 40. A slow wave member 48 is disposed on the planar antenna member 46. The slow wave member 48 has a high dielectric constant characteristic for shortening the wavelength of the microwave. The substantially entire surface of the upper portion and the side surface of the slow wave member 48 is covered by a waveguide case 50 composed of a conductive hollow cylindrical container. The planar antenna member 46 is configured as a bottom plate of the waveguide 50 and faces the loading table 26. Above the waveguide 50, a cooling jacket 52 through which the refrigerant is cooled is provided.

Both the waveguide box 50 and the peripheral portion of the planar antenna member 46 are electrically connected to the processing container 24. A tube 54A outside the coaxial waveguide 54 is connected to the center of the upper surface of the waveguide 50. The conductor 54B inside the coaxial waveguide 54 passes through the through hole at the center of the slow wave member 48 and is connected to the central portion of the planar antenna member 46.

The coaxial waveguide 54 is transmitted through a waveguide 60 in which the mode converter 56 and the matching circuit 58 are present, and is connected to, for example, a microwave generator 62 that generates a microwave of 2.45 GHz. Thereby, microwaves can be propagated toward the planar antenna member 46. The frequency of the microwave is not limited to 2.45 GHz, and other frequencies such as 8.35 GHz may be used.

When corresponding to a wafer having a size of 300 mm, the planar antenna member 46 is made of, for example, a conductive material having a diameter of 400 to 500 mm and a thickness of about 1 to several mm. More specifically, it may be composed of, for example, a copper plate or an aluminum plate whose surface is silver plated. The planar antenna member 46 is formed with a plurality of grooves 64 formed, for example, by long through-holes. The configuration of the groove 64 is not particularly limited. It may be arranged, for example, in a concentric shape, a spiral shape, a radial shape or the like. Or it can be distributed evenly over the entire surface of the planar antenna member.

Further, a gas introduction means 66 for supplying a gas required for etching to the processing container 24 is provided above the loading table 26. Specifically, the gas introduction means 66 is made of, for example, a gas nozzle made of quartz glass. The desired gas is supplied while controlling the flow rate by the gas nozzle 66 as needed. The gas nozzles can also be arranged in a plurality of ways depending on the type of gas used. Alternatively, the gas introduction means 66 may be constituted by a quartz shower head.

Further, for example, three lift pins 70 (only two in FIG. 1) for lifting and lowering the wafer W when the wafer W is carried in and out are provided below the loading table 26. The lift pin 70 is raised and lowered by a lifting rod 74 provided through the telescopic body 72 so as to penetrate the bottom of the container. Further, a through hole 76 for passing through the lift pin 70 is formed in the loading table 26.

The loading stage 26 as a whole is made of a ceramic such as a heat resistant material such as alumina. A heating means 78 is provided in the heat resistant material as needed. The heating means 78 of the present embodiment is constituted by a thin plate-shaped electric resistance heater which is buried in substantially the entire area of the loading table 26. The resistance heater 78 is connected to the heater power source 82 through the wiring 80 passing through the post 28. Further, the loading table 26 is provided with a cooling means (not shown) such as a cooling jacket as needed. Thereby, the semiconductor wafer W can be cooled to a predetermined temperature.

Further, a thin electrostatic chuck 84 having a mesh-like conductor line mounted inside is provided on the upper surface side of the loading table 26. In order to exert electrostatic attraction, the conductor wires of the electrostatic chuck 84 are connected to the DC power source 88 through the wiring 86. Thereby, the wafer W mounted on the loading table 26 in detail on the electrostatic chuck 84 can be adsorbed by electrostatic adsorption. On the other hand, in the wiring 86, a bias high-frequency power source 89 for applying a bias high-frequency power of, for example, 13.56 MHz to the conductor line of the electrostatic chuck 84 is connected as needed.

Next, the overall operation of the etching apparatus 22 is controlled by, for example, a device control unit 90 composed of a microcomputer or the like. The computer program for performing this operation is stored in a floppy disk or CD (Compact Disk: CD) or a memory medium 92 such as a flash memory or a hard disk. Specifically, the supply or flow rate control of each gas, the supply of microwave or high-frequency or power control, the control of the process temperature or the process pressure, and the like are performed by an instruction from the device control unit 90.

Next, an etching method performed using the etching apparatus 22 configured as described above will be described with reference to FIGS. 1 and 2.

<First Embodiment>

First, a first embodiment of the etching method of the present invention will be described.

As shown in FIG. 2A, the surface to be processed 2 to be etched is formed into a predetermined pattern on the surface of the object W to be formed on a semiconductor wafer such as a germanium substrate. The layer to be processed 2 is an insulating film made of, for example, a SiO ₂ film or the like. Further, only a part of the upper surface side of the object to be processed W is shown in the drawing.

Next, on the upper surface of the layer to be processed 2, an anti-reflection film 4 made of, for example, an organic material for the purpose of eliminating the adverse effect of the reflected light during the exposure of the photoresist described later is uniformly formed in advance. As the reflection preventing film 4, for example, BARC (trade name) can be used.

The surface of the anti-reflection film 4 of the object to be processed W formed in this manner is coated with a photoresist, and the photoresist layer 6 is first uniformly formed with a predetermined thickness (see FIG. 2A). Thereby, the photoresist forming step is completed.

Next, the photoresist layer 6 is selectively exposed and developed, and then a part thereof is selectively removed to form an etching recess 8 (see FIG. 2B). That is, the etching mask 10 composed of a photoresist is manufactured (refer to FIG. 2B). The etching recess 8 is formed in a groove shape or a hole shape depending on the pattern of the processed layer 2 to be removed. Further, in the bottom portion of the etching recessed portion 8, the lower layer of the anti-reflection film 4 is exposed here. Here, the width W1 of the etching recess 8 is about 150 nm or less, and the height H1 of the etching mask 10 is, for example, about 300 to 400 nm. The mask forming step is completed by the above method.

Next, the plasma etching process and the plasma CVD process are performed using the etching apparatus (plasma processing apparatus) 22 shown in FIG. In order to perform such plasma processing, first, the semiconductor wafer W shown in FIG. 2B is accommodated in the processing container 24 through the gate valve 30 by a transfer arm (not shown). By moving the lift pins 70 up and down, the semiconductor wafer W is loaded on the loading surface on the loading table 26. Then, the semiconductor wafer W is electrostatically adsorbed by the electrostatic chuck 84.

The semiconductor wafer W is maintained at a predetermined process temperature by means of heating means 78 or cooling means. On the other hand, the predetermined gas is supplied into the processing container 24 by the gas introduction means 66 at a predetermined flow rate. Next, the pressure control valve 34 is controlled to maintain the process vessel 24 within a predetermined process pressure. At the same time, the plasma generating means 44 is supplied to the planar antenna member 46 through the microwave generated by the microwave generator 62, that is, through the waveguide 60 and the coaxial waveguide 54. The microwave having a shortened wavelength is introduced from the planar antenna member 46 to the processing space S by the slow wave member 48. Thereby, the plasma is generated in the processing space S, and then the predetermined plasma processing is performed.

In detail, when microwaves are introduced from the planar antenna member 46 to the processing container 24, the gas originally introduced into the processing space S is plasma-activated and activated by the microwave, whereby the active center, semiconductor The surface of the wafer W can be efficiently subjected to plasma treatment (for example, an etching treatment to a film formation treatment) even at a low temperature. At this time, the high-frequency power source 89 for biasing is driven, whereby the ions in the plasma can be strongly pulled into the loading table 26 side.

Here, as described above, after the semiconductor wafer W shown in FIG. 2B is introduced into the plasma processing apparatus 22, as shown in FIG. 2C, the anti-reflection film 4 exposed at the bottom of the etching recess 8 is used. Plasma etching is removed. Thereby, the surface of the to-be-processed layer 2 is exposed. At this time, Ar gas, CF-based gas such as C ₅ F ₈ gas, ₀₂ gas, or the like can be used as the etching gas. Further, the heat resistance of the etching mask 10 is considered, and the process temperature is set to, for example, 130 ° C or lower. By the plasma etching treatment, the opening 10A of the etching recess 8 of the etching mask 10 is shaved a small amount, but there is no problem. The bottom reflection preventing film removing step is completed by the above.

Next, as shown in Fig. 2D, a plasma resistant film which is characterized by the present invention which is highly resistant to plasma is formed by plasma CVD on the entire surface of the etching mask 10 including the bottom and side surfaces of the etching recess 8 described above. 100. Thereby, the entire surface of the etching mask 10 is covered with the plasma resistant film 100. For example, tantalum nitride (SiN) can be used as the plasma resistant film 100. The main point here is that since the width W1 of the etching recess 8 is extremely narrow, it is difficult for the film forming gas to intrude into the inside. Therefore, the thickness T1 of the plasma-resistant film 100 deposited on the bottom and the side surfaces of the etching recess 8 is much thinner than the thickness T2 of the plasma-resistant film 100 deposited on the etching mask 10. Although the width W1 or the height H1 of the concave portion 8 for etching differs, the ratio T1/T2 of the two thicknesses is, for example, about 0.5. Here, the plasma resistant film 100 is formed into a film, and the thicknesses T1 and T2 of the plasma resistant film 100 are, for example, about 5 nm and 10 nm, respectively.

At this time, the process temperature also considers the heat resistance of the etching mask 10, and is set to, for example, 130 ° C or lower. Further, in the film forming gas at this time, a decane-based gas and a nitriding gas are used. Here, SiH ₄ gas or Si ₂ H ₆ gas can be used as the decane-based gas. Further, N ₂ gas or NH ₃ gas can be used as the nitriding gas. Further, an inert gas such as an Ar gas may be added to the gas. The plasma resistant film forming step is completed by the above method.

Next, as shown in FIG. 2E, a plasma etching treatment for removing the plasma resistant film 100 deposited on the bottom of the etching recess 8 is applied. At this time, the plasma resistant film 100 deposited on the etching mask 10 is also cut off at the same time, but as described above, since the film thickness T2 of the portion is much thicker than the film thickness T1 at the bottom, it can be deposited only at the bottom. The plasma resistant film 100 is completely removed. Thereby, the surface of the underlying processed layer 2 is exposed at the bottom of the etching recess 8 . Further, at this time, when the bias high-frequency power source 89 is driven and the bias current for ion extraction of 13.56 MHz is applied to the loading stage 26, the plasma-resistant film 100 deposited on the bottom can be more efficiently removed.

A CF-based gas such as CF ₄ gas or CHF ₃ gas can be used as the etching gas at this time. Further, the heat resistance of the etching mask 10 is considered, and the process temperature is set to, for example, 130 ° C or lower. In this way, the bottom plasma resistant film removal step is completed.

Next, as shown in FIG. 2F, the etched reticle 10 covered with the plasma resistant film except the bottom of the etching recess 8 is used as a mask, and the layer 2 to be processed is subjected to plasma etching treatment. Thereby, for example, the processed layer ₂ composed of SiO _{2 ,} that is, the pattern of the etching mask 10 covered with the transfer plasma resistant film is etched to form, for example, the processing groove 12 . The surface of the underlying semiconductor wafer W is exposed at the bottom thereof.

The heat resistance of the etching mask 10 is considered, and the process temperature is set to, for example, 130 ° C or lower. Further, for example, a CF-based gas composed of CF ₄ gas, an Ar gas, or the like can be used as the etching gas at this time.

At this time, with the plasma etching treatment, the plasma resistant film 100 made of SiN is also cut off, and the whole is thinned. However, the selection ratio of SiN of the plasma-resistant film 100 by the etching gas to the SiO ₂ of the layer to be processed 2 is about 10 to 50, that is, it is relatively easy to be compared with the layer 2 to be processed composed of SiO ₂ . After cutting, the plasma resistant film 100 is not completely cut off. That is, the shape of the etching mask 10 is maintained, and the shape does not collapse. Further, when an etching gas composed of a C ₅ F ₈ gas is used, the above selection ratio can be further improved.

Therefore, as shown in Figs. 4D and 4E, the etching pattern has collapsed in the conventional method, and according to the method of the present invention, as described above, it is possible to more reliably prevent deformation of the etching mask 10 without shape. The desired etching pattern for collapse. With the above, the formal etching step is completed.

Next, as shown in Fig. 2G, a plasma etching treatment is applied to completely remove the plasma resistant film 100 made of SiN covering the surface of the etching mask 10. Here, contrary to the case of FIG. 2F, the plasma resistant film 100 made of SiN is easily removed on the one hand, but the etching gas of the processed layer 2 made of SiO ₂ is not easily removed on the other hand. Specifically, by using a CF-based gas, for example, by setting CF ₄ gas at an appropriate concentration or by using CHF ₃ gas as such an etching gas, the opposite of the case illustrated in Fig. 2F can be obtained. ratio. Thereby, the plasma resistant film 100 covering the etching mask 10 can be selectively removed while maintaining the original shape of the processed layer 2 made of SiO ₂ . By the above, the plasma resistant film removing step is completed.

Next, as shown in Fig. 2H, plasma ashing treatment using, for example, oxygen plasma is performed. Specifically, a mask removal step of removing the etching mask 10 made of an organic material is performed, and then an anti-reflection film removing step of removing the anti-reflection film 4 made of an organic material is performed. Thereby, the etching mask 10 and the anti-reflection film 4 are completely removed, respectively. By the above, a series of etching processes are ended.

In this manner, according to the present invention, the plasma resistant film 100 is formed on the entire surface of the etching mask 10, and since the plasma resistant film 100 located at the bottom of the etching recess 8 of the etching mask 10 is removed, the chipping is performed. Since the processing layer 2 is generally subjected to etching treatment, it is possible to surely obtain an etching pattern which is capable of preventing the etching mask from being deformed and having no shape collapse.

In the above embodiment, from the plasma etching treatment shown in FIG. 2C to the plasma ashing treatment shown in FIG. 2H, the type of gas used for the supply is switched, but the plasma etching treatment shown in FIG. The device 22 is continuously performed. However, the present invention is not limited to this embodiment. From the processing shown in FIG. 2C to the processing shown in FIG. 2H, only a part of the processing may be performed in the plasma etching processing apparatus 22 shown in FIG. 1, and other processing may be performed. The processing device is carried out. For example, the plasma etching treatment, the plasma CVD treatment, and the plasma ashing treatment may be performed separately in a dedicated processing apparatus. Alternatively, the processing steps from the processing shown in FIG. 2C to the processing shown in FIG. 2H may be performed on different processing devices.

<Second embodiment>

Next, a second embodiment of the present invention will be described.

3A to 3H are process diagrams showing a second embodiment of the etching method of the present invention. In the first embodiment described above, in each step shown in FIG. 2C to FIG. 2E, after the etching mask 10 is formed, the anti-reflection film 4 exposed to the bottom of the etching recess 8 is removed (see FIG. 2C). Next, the plasma resistant film 100 (see FIG. 2D) is deposited on the entire surface, and then the plasma resistant film 100 located at the bottom of the etching recess 8 is removed (see FIG. 2E). However, the plasma resistant film 100 may be deposited first, and then the plasma resistant film 100 and the anti-reflection film 4 located at the bottom of the etching recess 8 may be sequentially removed. That is, in the present embodiment, the steps shown in FIG. 3A and FIG. 3B correspond to the steps shown in FIG. 2A and FIG. 2B respectively. When the etching mask 10 shown in FIG. 3B is completed, as shown in FIG. 3C. As shown, the plasma resistant film 100 is formed on the entire surface of the etch mask 10.

Next, as shown in FIG. 3D, the plasma-resistant film 100 deposited on the bottom of the etching recess 8 is removed, and the anti-reflection film 4 exposed to the bottom of the etching recess 8 is removed as shown in FIG. 3E.

Thereafter, the steps shown in FIGS. 3F to 3H correspond to the steps shown in FIGS. 2F to 2H, respectively.

In the present embodiment of the above aspect, the same operational effects as those of the first embodiment can be exhibited.

Further, in each of the above embodiments, a case where a tantalum nitride film (SiN) is used as the plasma resistant film 100 will be described as an example, but the invention is not limited thereto. For example, a SiCN film, a SiC film, a SiCO film, a Si film, or the like can also be used. Further, in the films exemplified herein, which include the SiCN film, a small amount of hydrogen is also contained. This situation is also included in the scope of the invention. Further, when a film containing Si and C is formed at a low temperature (130 ° C or lower) as the plasma resistant film 100, at least trimethyl decane is preferably used.

When each of the above films is used as the plasma resistant film 100, when these films are removed by plasma etching, CF ₄ gas or CHF ₃ gas may be used in the same manner as in the case of the SiN film.

Further, in each of the above embodiments, the case where the insulating film made of SiO ₂ as the processed layer 2 is etched is described as an example, but the present invention is not limited thereto. The case where the insulating film of another film type is etched is also applicable to the present invention.

Further, the present invention is not limited to the insulating film. For example, when a conductive polysilicon film is etched as the processed layer 2, the present invention is also applicable. In this case, the plasma-resistant film 100 can be used in addition to the Si film, among the previously listed film types which can be used when the layer 2 to be processed is an SiO ₂ film.

Further, the plasma processing apparatus shown in Fig. 1 is merely an example. The method of the invention can be applied to all other plasma processing devices using microwaves or high frequencies.

Further, the system to be processed is not limited to a semiconductor wafer, and the present invention can be applied as an object to be processed, such as an LCD substrate, a glass substrate, and a ceramic substrate.

2. . . Processed layer

4. . . Anti-reflection film

6. . . Photoresist layer

8. . . Etching recess

10. . . Etching mask

10A. . . Etching the opening of the recess for etching the mask

12. . . Processing tank

twenty two. . . Etching device

twenty four. . . Processing container

26. . . Loading station

28. . . pillar

30. . . gate

32. . . exhaust vent

34. . . Pressure control valve

36. . . Vacuum pump

38. . . Exhaust path

40. . . roof

42. . . Sealing member

44. . . Plasma formation means

46. . . Planar antenna member

48. . . Slow wave

50. . . Guide box

52. . . Cooling sleeve

54. . . Coaxial waveguide

54A. . . Coaxial waveguide

54B. . . Conductor inside the coaxial waveguide

56. . . Mode converter

58. . . Matching circuit

60. . . Waveguide

62. . . Microwave generator

64. . . groove

66. . . Gas introduction means

70. . . Lift pin

72. . . Telescopic body

74. . . Lifting rod

76. . . Through hole

78. . . Heating means

80. . . Wiring

82. . . Heater power supply

84. . . Electrostatic chuck

86. . . Wiring

88. . . DC power supply

89. . . High frequency power supply

90. . . Device control unit

92. . . Memory media

100. . . Plasma resistant film

202. . . Processed layer

204. . . Anti-reflection film

206. . . Photoresist layer

208. . . Etching recess

210. . . Etching mask

210A. . . Etching the opening of the reticle

212. . . Processing groove of processed layer

212A. . . Opening of the processing groove of the processed layer

H1. . . Height of the recess for etching

S. . . Processing space

T1. . . Thickness of plasma resistant film

T2. . . Thickness of plasma resistant film

W. . . Object to be processed

W1. . . Width of the recess for etching

Fig. 1 is a schematic cross-sectional view showing an etching apparatus according to an embodiment of the present invention.

2A to 2H are process diagrams showing an etching method according to the first embodiment of the present invention.

3A to 3H are process diagrams showing an etching method according to a second embodiment of the present invention.

4A to 4E are process diagrams showing an example of a conventional etching method using plasma.

2. . . Processed layer

4. . . Anti-reflection film

6. . . Photoresist layer

8. . . Etching recess

10. . . Etching mask

10A. . . Opening portion of the recess for etching

12. . . Processing tank

100. . . Plasma resistant film

H1. . . Etching the height of the reticle height

T1. . . Thickness of plasma resistant film

T2. . . Thickness of plasma resistant film

W. . . Object to be processed

W1. . . Width of the recess for etching

Claims (6)

An etching method for etching a layer to be processed formed on a surface of a target object, comprising: a photoresist forming step of uniformly forming a photoresist layer on a surface of the object to be processed; and a mask forming step Forming a predetermined etching recess in the photoresist layer to form a patterned etching mask; and a plasma resistant film forming step comprising forming a bottom portion and a side surface of the etching recess to form an entire surface of the etching mask a plasma resistant film; a bottom plasma resistant film removing step of removing the plasma resistant film formed on the bottom of the etching recess; and a formal etching step after the bottom plasma resistant film removing step The etch mask is used as a mask to etch a layer to be processed before, and the thickness of the plasma resistant film formed on the bottom of the front etching recess is thinner than the thickness of the plasma resistant film formed on the etch mask. The plasma resistance is formed by plasma CVD treatment at a temperature lower than a heat resistance temperature of the etching mask, and the surface of the processed layer is formed in advance. Reflection preventing film. The etching method according to the first aspect of the invention, wherein the bottom anti-reflection film removing step is performed before or after the plasma-resistant film forming step to remove the anti-reflection film located at the bottom of the etching recess. The etching method according to the first aspect of the invention, wherein, after the main etching step, sequentially performing: a plasma film removal step of removing the plasma resistant film; and a mask removal step of removing the mask . An etching method as recited in claim 1, wherein Part or all of the plasma-resistant film forming step, the bottom plasma film-removing step, and the above-described main etching step are performed in the same plasma processing apparatus. An etching apparatus for applying a predetermined etching treatment to a target object, comprising: a processing container capable of being evacuated; a loading stage provided in the processing container for loading the object to be processed; and a predetermined gas; a gas introduction means introduced into the processing container; a plasma forming means for slurrying the predetermined gas in the processing container; and a device control unit for controlling the gas introducing means and the plasma forming means The following step, that is, a plasma resistant film forming step of forming a plasma resistant film on the entire surface of the etching mask formed on the surface of the processed layer of the object to be processed, and a bottom plasma resistant film removing step And removing a plasma-resistant film formed on the bottom of the etching recess formed on the etching mask, or a part or all of the steps in the main etching step, except for the bottom of the etching recess The etching mask covered with the plasma resistant film is used as a photomask to etch the processed layer. A memory medium for storing a computer program for causing a computer to implement a control method for controlling a processing container having a vacuum that can be evacuated; and a loading station for loading the object to be processed in the processing container a gas inlet means for introducing a predetermined gas into the processing container; and an etching device for plasmaizing the predetermined gas in the processing container, and controlling the gas inlet means and the plasma And a step of forming a plasma resistant film formed by etching light formed on a surface of the processed layer of the object to be processed Forming a plasma resistant film and a bottom plasma resistant film removing step on the entire surface of the cover, which removes the plasma resistant film formed on the bottom of the etching recess formed on the etching mask, and a part of the formal etching step In the step or the whole step, the processed layer is etched by using the etching mask covered with the plasma resistant film as a mask, except for the bottom of the etching recess.